WASHINGTON (Reuters) - Republican U.S. Senator Saxby Chambliss announced on Friday he will not run for a third term in 2014, saying he was fed up with a lack of leadership in the White House and partisan gridlock in Congress.

Targeted by the conservative Tea Party movement for backing a year-end deal that raised taxes on the wealthy, the Georgia lawmaker was one of the few Republicans willing to sit down with Democrats on fiscal issues.

"This is about frustration, both at a lack of leadership from the White House and at the dearth of meaningful action from Congress, especially on issues that are the foundation of our nation's economic health," Chambliss said in a statement.

During December's negotiations to avoid the New Year's Day austerity measures, Chambliss rebelled against anti-tax lobbyist Grover Norquist and said he was open to President Barack Obama's plan to raise taxes on the wealthy.

He was criticized by fellow conservative lawmakers, who have signed Norquist's "taxpayer protection pledge." But Chambliss said he cared "more about this country" than he did about a 20-year-old pledge.

Congress eventually passed a last-minute deal that extended tax breaks for all Americans except families earning more than $450,000 per year.

But fiscally conservative activists were irate with lawmakers for raising taxes without cutting spending and started looking for replacements for Chambliss and other Republicans who backed the deal.

No one had yet announced a Republican primary challenge to Chambliss, although U.S. Representatives Tom Price and Paul Broun were seen as potential candidates.

Chambliss is a member of the so-called Gang of Eight group of senators, a bipartisan alliance working for deficit reduction that has so far failed to come up with a viable plan.

"Sadly, I don't see the legislative gridlock and partisan posturing improving any time soon," he said.

Chambliss is the second Republican senator to resign partly due to Congress' inability to get anything done. Olympia Snowe, the only Republican to vote for Obama's healthcare bill in the Senate Finance Committee, retired from the Senate for similar reasons.